Housings for electric circuits are quite familiar from the state of the art. Particularly in the automotive realm, electronic control circuits are protected by means of a control-unit housing. These control units are especially employed in the engine compartment, where they are exposed to considerable temperature fluctuations that can lead to major pressure fluctuations inside the housing. In order to compensate for these pressure fluctuations, in a simple case, all that is needed is to make drilled holes or openings through which the pressure differentials can be equalized. A drawback of these approaches is that an exposed opening can also allow water to get directly into the housing, where it can cause damage. In order to prevent water from penetrating directly into the housing, it is a known procedure from the state of the art to employ so-called semi-permeable membranes that are arranged over a venting opening and that allow air as well as water vapor to enter or exit through the membrane, whereas water in liquid form is not allowed to pass through.
It is already a known procedure from German patent application DE 41 40 487 A1 to use a control unit or switching device in which a pressure equalizing element is injection-molded into a cutout of a plug strip in the body of the housing. The venting to the outside takes place here through several drilled holes offset with respect to each other.
Moreover, German patent application DE 10 2007 035 094 A1 discloses a housing for an electric circuit that has an electric plug connector and a pressure equalizing element that is covered by a protection element or a cover hood. Here, at least one pressure equalizing opening of the protective cap is oriented in the direction of a plug connector.